1. Field of the Invention
The present invention relates to an image-forming liquid medium containing microcapsules filled with dye or ink, and to an image-forming apparatus that forms an image on a sheet of recording paper by selectively developing monochromatic dots, when using such an image-forming liquid medium, in accordance with a series of digital image-pixel signals.
2. Description of the Related Art
Conventionally, an image-forming system, using an image-forming sheet coated with a layer of microcapsules filled with dye or ink, is known. In this image-forming sheet, a shell of each microcapsule is formed of a suitable photo-setting resin, and an optical image is recorded and formed as a latent image on the layer of microcapsules by exposing it to light rays in accordance with image-pixel signals. Then, the latent image is developed by exerting pressure on the microcapsule layer. Namely, the microcapsules, which are not exposed to the light rays, are squashed and broken, whereby the dye or ink seeps out of the squashed and broken microcapsules, and thus the latent image is visually developed by the seepage of the dye or ink.
Of course, in this conventional image-forming system, it is impossible to form an image on a sheet of ordinary printing paper without the layer of microcapsules. Nevertheless, usually, only a small portion of the microcapsules included in the layer contributes to the formation of an image on the image-forming sheet. In other words, a large portion of the microcapsules included in the layer are not utilized for the formation of an image on the image-forming sheet. Thus, in the conventional image-forming system, a large amount of ink or dye, encapsulated in the microcapsules, is wastefully consumed by not taking part in the formation of an image.
Also, each of the image-forming sheets must be packed so as to be protected from being exposed to light, resulting in wastage of materials. Further, the image-forming sheets must be handled such that they are not subjected to excess pressure due to the softness of unexposed microcapsules, resulting in an undesired seepage of the dye or ink.